Abrading machine tool



Dec. 14, 1965 c. L. KASTL ABRADING MACHINE TOOL Filed Aug. 16, 1963 INVENTOR.

CHARLES L. KASTL United States Patent 3,222,826 ABRADING MACHINE TOOL Charles L. Kastl, 5248 E. Virginia, Phoenix, Ariz. Filed Aug. 16, 1963, Ser. No. 302,601 Claims. (Cl. 51-358) This invention relates to an abrading machine tool and more particularly to an abrading machine tool which is particularly adapted for use in the lapidary art for finishing stones, gems and semiprecious gems, or the like.

In the hand finishing of various stones such as gems or semiprecious gems much manual handling is required and in many instances gems are finish crowned in connection with a dop stick which is used to handle the gems while they are placed against a moving abrasive medium.

Various prior art devices used for this purpose include rotary drums having external surfaces surrounded by abrasive belts or the like. In many instances these abrasive belts cannot be operated dry, and must be supplied with a constant stream of water. Such operations cause centrifugal dispersion of the water from the periphery of the abrasive surface, thus creating undesirable wetting conditions of surrounding areas and requiring various type shields.

Many of the lapidary devices which use strips of abrasive material, such as the abrasive coated cloth belts, require complicated means for attaching the belts to the peripheries of buffing wheels, all of which require time of the operator to change these belts when changing from a coarse grit to a relatively finer grit during the finishing operations on various pieces of work.

Accordingly, it is an object of the present invention to provide a drum on the interior of which a soft resilient liner is provided with an inner annular abrasive material whereupon water on the abrasive material is centrifugally retained in the drum and on the abrasive surface so that a stone secured to a dop stick may readily be finished on the abrasive surface, and the water or other coolant may remain inside the drum Without being centrifugally dispersed therefrom.

Another object of the invention is to provide an abrading machine tool which employs a rotating drum having an interior annular surface adjacent to which annular soft resilient liner structure and abrasive belt structure is centrifugally supported whereby these liners and abrasive belts are readily removable and replaceable.

Another object of the invention is to provide a lapidary device having a rotating shaft which supports a drum having an annular wall internally of which a soft resilient liner removably supports an abrasive belt whereby the abrasive belt may readily and quickly be changed from one abrasive grade to another during progressive finishing of a gem or other workpiece, as desired.

Another object of the invention is to provide a novel abrading machine tool particularly adapted for lapidary work and wherein an annular soft resilient liner is supported by an inner annular wall of a drum disposed to rotate and permit deflection of an abrasive material internally of the soft resilient liner so that the abrasive material readily conforms to the general crown curvature of a gem or other workpiece being finished thereby.

Another object of the invention is to provide a very simple and economical abrading machine tool which is particularly useful in the lapidary art.

Further objects and advantages of the invention may be apparent from the following specification, appended claims and accompanying drawings in which:

FIGURE 1 is a side elevational view of an abrading machine tool of the invention showing portions thereof broken away and in section to amplify the illustration;

3,222,826 Patented Dec. Ml, 1965 FIGURE 2 is an enlarged fragmentary sectional view taken from the line 22 of FIGURE 1;

FIGURE 3 is an open end view of the drum of the invention taken from the line 3-3 of FIGURE 1 and showing a gem connected to a dop stick and illustrating by broken lines and arrows movement of the dop stick relative to the drum of the invention and an abrasive liner therein, so that the gem will be provided with a smooth symmetrical crown;

FIGURE 4 is an enlarged fragmentary sectional view of a dop stick in connection with a gem to be finished;

FIGURE 5 is a view similar to FIGURE 3 showing a modification of the soft resilient liner and the abrasive means of the invention; and

FIGURE 6 is an enlarged fragmentary sectional view of a modification of the device shown in FIGURE 1 of the drawings.

As shown in FIGURE 1 of the drawings, a shaft 10 is rotatably mounted in any conventional manner and may be supported by various types of bearings to operate in a horizontal axial position. The shaft 10 is preferably motor driven and fixed thereon is a collar 12 having a setscrew 14 engageable with the shaft 10 to lock the collar 12 thereon.

The collar 12 is provided with a flange 16 connected to a closed side 18 of a cup shaped drum structure 2%. This drum structure 20 may be deep-drawn or spun, or may be formed of plastic if desired. The drum 20 is provided with a annular rim 22 at its open side 24 which is opposite to the enclosed end 18 secured to the shaft 10 by the collar 12.

The drum 20 is provided with an annular wall 26 having an internal surface 28 engaged by a soft resilient annular liner 30 internally of which is an annular abrasive belt 32 having its abrasive facing inwardly. As shown in FIGURE 2 the abrasive belt 32 is provided with an abrasive surface 34 directed inwardly, and this abrasive surface 34 may be composed of silicon carbide or any other suitable abrasive. The abrasive strip 32 as shown in FIGURE 3 is provided with opposite ends 36 and 38 which are abutted internally of the soft resilient liner 30. This liner 30 is provided with opposite ends 38 and 40 which are abutted adjacent the inner surface 28 of the drum 26.

It will be appreciated by those skilled in the art that the silicon carbide abrasive material on the surface 34 of the abrasive strip 32 may vary in grade from 220 to 600 grit, for example. It will be seen that the abrasive strip 32 as shown in FIGURE 3 of the drawings is internally of the soft resilient liner 30, and it in turn is supported on the inner annular surface of the drum 2%). When the drum 20 is rotated by the shaft 10, centrifugal loading of the abrasive strip 32 and the liner 30 hold them in place in the drum 20 and thus the abrasive strip 32 stays in position during use and may readily be removed so that a similar abrasive strip may be substituted for a worn one, or in order to substitute for a different abrasive grades material.

It is common in the lapidary arts to start with a relatively coarse grade, such as 220, and finish with an abrasive grade commonly known as 600.

In conventional practice a gem or stone, as shown in FIGURE 4 of the drawings, may be provided with a conventional crown 42 which is first formed in a rough ground configuration. A conventional bezel 44 and safety bezel 46 may also be rough ground and eventually finish ground on this stone. Conventional dopping wax 48 is used to cement a dop stick 50 to the stone, and the dop stick 50 may then be moved in a substantially circular path, as indicated by arrows 52, while the crown 42 of the stone is adjacent to and in contact with the abrasive 34 while the drum rotates as indicated by an arrow A in FIGURE 3 of the drawings. As the drum rotates water on the inner surface and on the abrasive 34 is retained centrifugally so that it does not leave the abrasive surface 34 and slight pressure on the dop stick 50 causes the crown 42 to indent the abrasive strip 32 and the soft resilient liner 30, which may be made of sponge rubber or any other suitable material. Thus deflection of the liner 30 may conform to the general geometric curvature of the crown 42 and movement of the dop stick 50, as hereinbefore described, causes the abrasive 34 smoothly to finish the crown 42. Action of the soft resilient liner 30 deflecting under pressure of the dop stick 50 and the stone 42 permits fine faired finishing of the crown 42, and, as hereinbefore described, the belt or abrasive strip 32 may be changed from time to time in order to obtain different and similar belts having different grades of abrasive thereon.

As shown in FIGURE of the drawings, an abrasive belt 54 is endless and circular and is surrounded by a soft resilient liner 56. These are concentrically disposed in the drum 20 and may be placed therein by initially having a portion of the belt 54 and the liner 56 disposed in a crimped broken line position 58 whereupon this portion is forced toward the drum 20 as indicated by an arrow B in FIGURE 5, thus causing the entire abrasive strip and liner structure to snap into the solid line position shown in FIGURE 5 of the drawings and to thereby be compressively secured in the drum 20 adjacent its inner surface 28.

In the modification as shown in FIGURE 6 of the drawings, the drum 20 is provided with annular concave grooves 60 and 62 and a conforming liner 64 conforms with these annular grooves 60 and 62 and the liner 64 is provided with internal annular grooved surface portions 66 and 68 directed inwardly from the grooves 60 and 62, respectively.

The liner 64 may be made of semirigid material or lead, or any other suitable material to provide a fixed geometry lap whereby the arcuate grooved annular recesses 66 and 68 will retain water or other coolant while the drum 20 rotates and will substantially conform to the geometric curvature of the crown 42 of the stone 44. These liners 64, according to the modification shown in FIGURE 6 of the drawings, are thus substantially rigid and are not soft, resilient liners. Due to the annular curved groove 68 the crown 42 of the stone 44 may be ground smoothly and the surfaces properly faired during finishing, as desired.

It will be obvious to those skilled in the art that various modifications of the present invention may be resorted to in a manner limited only by a just interpretation of the following claims.

I claim:

1. In an abrading machine tool the combination of: a drum; a shaft rotatably supporting said drum; an annular wall of said drum extending longitudinally and parallel with the axis of said shaft; said shaft connected to one end of said drum; an opposite end of said drum being open; a soft resilient liner carried on the interior of said annular wall; and abrasive material carried on an interior portion of said resilient liner; said resilient liner and said abrasive material readily removably supported frictionally and centrifugally in said drum; said liner having opposite ends abutted with each other.

2. In an abrading machine tool the combination of: a hollow drum; a shaft rotatably supporting said drum; an internal annular concave wall of said drum extending longitudinally and parallel with the axis of said shaft; said shaft connected to one end of said drum; an opposite end of said drum being open; a soft resilient liner carried on the interior of said annular wall; and abrasive material carried on an interior portion of said resilient liner; said resilient liner and said abrasive material readily removably supported in said drum; a thin strip separate from said liner and carrying said abrasive material; said thin strip having opposite ends abutted to each other, said liner surrounded and supported centrifugally and frictionally by said annular concave wall.

3. In an abrading machine tool the combination of: a drum; a shaft rotatably supporting said drum; an annular Wall of said drum extending longitudinally and parallel with the axis of said shaft; said shaft connected to one end of said drum; an opposite end of said drum being open; a soft resilient liner carried on the interior of said annular wall; and abrasive material carried on an interior portion of said resilient liner; said resilient liner and said abrasive material readily removably supported in said drum; a thin strip separate from said liner and carrying said abrasive material; said thin strip having opposite ends abutted to each other; said strip readily removably supported in said liner and when said drum is rotated said liner and said strip being centrifugally held toward the inside of said annular wall.

4. In an abrading machine tool the combination of: a drum; a shaft rotatably supporting said drum; an annular wall of said drum extending longitudinally and parallel with the axis of said shaft; said shaft connected to one end of said drum; an opposite end of said drum being open; a soft resilient liner carried on the interior of said annular wall; and abrasive strip carried on an interior portion of said resilient liner; said strip having opposite ends abutted to each other; said strip being readily removably mounted in said liner; said strip surrounded by said line and centrifugally supported therein.

5. In an abrading machine tool the combination of: a drum; a shaft rotatably supporting said drum; an annular wall of said drum extending longitudinally parallel with the axis of said shaft; said shaft connected to one end of said drum; an opposite end of said drum being open; a liner carried on the interior of said annular wall; abrasive material carried on an interior portion of said liner, said annular wall having a concave annular groove in its inner surface; said liner having a conforming annular groove structure corresponding to and fitted in the annular groove of said annular wall.

References Cited by the Examiner UNITED STATES PATENTS 3/1879 Place. 10/1945 Fruth 51289 

1. IN A ABRADING MACHINE TOOL THE COMBINATION OF: A DRUM; A SHAFT ROTATABLY SUPPORTING SAID DRUM; AN ANNULAR WALL OF SAID DRUM EXTENDING LONGITUDINALLY AND PARALLEL WITH THE AXIS OF SAID SHAFT; SAID SHAFT CONNECTED TO ONE END OF SAID DRUM; AN OPPOSITE END OF SAID DRUM BEING OPEN; A SOFT RESILIENT LINER CARRIED ON THE INTERIOR OF SAID ANNULAR WALL; AND A BRASIVE MATRIAL CARRIED ON AN INTERIOR PORTION OF SAID RESILIENT LINER; SAID RESILIENT LINER AND SAID ABRASIVE MATERIAL READILY REMOVABLY SUPPORTED FRICTIONALLY AND CENTRIFUGALLY IN SAID DRUM; SAID LINER HAVING OPPOSITE ENDS ABUTTED WITH EACH OTHER. 